Roller bit with parallel inlayed compacts

ABSTRACT

This invention relates to a roller bit applying for the oil, natural gas, mine and geological drilling, and more particularly relates to a kind of roller bit with the parallel inlayed compacts, it includes head and cone, the compact land and the teeth-groove are arranged on the cone, the difference is that there are 2 to 3 compacts having the cylindrical body being arranged on the top of the base teeth along the teeth direction. The cutting performance of the present invention is similar to that of the oblate compacts, and, by utilizing the conventional cylindrical compacts, it is not only easy to process and with low manufacturing cost, but the bit can effectively drill through the stringered earth formation with both hard and soft formation and thus better economic benefit from drilling the stringered formation can be obtained.

[0001] This invention relates to a roller bit applying for the oil, natural gas, mine and geological drilling, and more particularly relates to a roller bit with parallel inlayed compacts.

[0002] Roller bits have been widely used as a tool for earth boring. A roller bit usually consists of the cone and the head. The cone may be one or more, and the head is moveably attached with the cone inner hole through the suspending-arm shaft at the lower part, so that the cone can rotate around shaft. The cutting structure of the outer surface of the cone may crush the rock formation under the action of the impact, crush and the slide shearing generated by the combining movement of the cutting structure with the revolution, self-rotation and the axial advancement of the cone. The prior roller bits are divided into two sorts which are steel-teeth bit and the compact bit, the teeth and the cone of the steel-teeth bit are integrally formed, with the more broad teeth cutting edge which can effectively scrape and chisel the soft earth formation, but when the hard formation is reached, the steel-teeth is easily worn and with a result of loosing the cutting function. Even when coated with an abrasion-resistant material, the steel-teeth still crack or break when they encounter hard formations. For the geological formation with stringers, when the steel-teeth bit is used and can not effectively drill through the hard formation, the compact roller bit must be used. The compacts are usually made from carbide, with higher hardness and being more wear-resistant, but the cutting edge of the compact is not broad, by which can not effectively drill the soft formation. From this we can see that the present steel teeth bit and compact bit both can not be effectively applied for the formation with stringers. In order to overcome the above problems, U.S. Pat. No. 5,421,423 discloses a kind of roller cone bit having the oblate compact with longer crest, although it can be effectively applied for the stringered earth formation, but the interference fit between the oblate compact and the oblate holes on the cone needs the compact as well as the holes with high machining precision, so the manufacture of such roller bit with the oblate compact is more difficult, low efficient and low cost-effective.

[0003] The object of this invention is to overcome the above problems and to provide a roller bit with the parallel compact, it is not only easy to machine, but also to have low cost, and can drill through earth formation effectively.

[0004] The object of this invention can be realized by the following aspects: the roller bit according to present invention is constructed of head and cone, the cone is a member for breaking the rock, there are compacts on the cone for breaking the rock, and the head is for supporting the cone, at the lower part of the head is the cantilevered shaft, the cone is mounted on the head shaft by means of locking mechanism and the bearing couple which being formed by the cone inner hole and the shaft of the head, the cone can rotate around the shaft. Several compact lands and grooves are arranged on the cone, the compact lands are machined into several base teeth by milling, and two to three smaller cylindrical holes are parallelly machined on top of the base teeth along the direction of the teeth, and also the smaller cylindrical compacts are inlayed into the corresponding cylindrical holes, thus can form a kind of roller-bit with the parallel inlayed compacts cutting structure.

[0005] According to the above aspects, the gap between the parallel inlayed compact may be 2 to 5 mm, the base of the compact is cylindrical in shape which is interference fitted with the circular holes on the cone, the crest of the compact is of wedge shape, and having a longer cutting edge, the teeth formed along the compact land can be the shape of straight taper and straight teeth, or can be the shape of spiral taper and spiral straight teeth, the spiral angle α is 0 to 15 degrees.

[0006] According to this invention, it has the following advantages: 1. By employing the parallel compacts, the cutting performance is similar to the oblate compacts, and can have the longer cutting edge, and also the noncontinuous long crest constructed thereby is easy to engage the earth formation, thus helpful to improve the rock breaking efficiency and the life of the bit. In addition, the teeth-groove and the annular separating groove can take the advantage of chip removing, improvement of the cutting condition, and preventing from bit balling; 2. By adopting the conventional compacts with cylindrical body, it is not only easy to machine, but also have high fitting precision, so the product quality can be guaranteed, and with a low manufacture cost and good economy; 3. The roller bit can drill through the hard earth formation, and can also drill through the soft earth formation with scraping action, so it is effective to be applied for the stringered earth formation, and therefor the drilling efficiency is further increased.

[0007]FIG. 1 is a partially cross-section view of the roller bit being taken partially according to one embodiment of this invention;

[0008]FIG. 2 is the front cross-section view of a cone according to one embodiment of this invention;

[0009]FIG. 3 is the top view of the cone according to one embodiment of this invention;

[0010]FIG. 4 is the top view of a cone according to another embodiment of this invention.

[0011] Now the detailed description will be given referring to the drawings. FIG. 1 is a partially cross-section view of the roller bit being taken partially according to one embodiment of this invention, the roller bit according to this invention includes the head 1 and the cone 3, the head 3 is coupled with the cone 3 through the suspending-arm shaft at the lower part thereof, the bearing couple are constructed by the bearing pin 2 and the cone inner hole. The steel locking ball 5 movably connects the cone 3 with the bearing pin 2 of the head, the rolling member 6 and the sealing ring 7 are arranged between the cone inner hole and the bearing pin, the sealing ring 7 can prevent the lubrication grease inside the bearing from leaking outside as well as prevent the drilling liquid outside from entering into the bearing, the ball plug 8 on the head is for locking the steel ball 5 in position, the lube hole 9 is the passage for supplying the lubricating grease to the bearing. The structure of the cone is shown in FIG. 2 and FIG. 3, there is a connecting hole 13 in the cone, which forms the bearing couple together with the bearing pin of the head, the cone is in the shape of straight taper, and there are two compact lands 10, one upper and one lower, are thereof respectively, and also four layers of compact lands can be formed in this embodiment, the annular separating groove 11 is arranged between the compact lands, and the teeth-grooves 12 are made on each of the compact land, from this the base teeth are formed, the base teeth is in the shape of straight taper, the direction of the teeth is the same as that of generatrix of the cone body, and also two compacts 4 are parallelly arranged on the top of the base teeth along the direction of the base teeth, the compact is made of carbide and with the normal shape, but it can also be made from other hard materials, the compact body is in the shape of cylinder which is firmly inlayed into the circular hole on the cone by interference fit, the crest of the compact is in the shape of wedge, and the gap between the two compacts is 3 mm.

[0012] The second embodiment of this invention is shown in FIG. 4, the main difference from the above embodiment is that the teeth direction of the base teeth bias an angle relative to the generatrix of the cone body, the base teeth is in the shape of the spiral taper, the spiral angle α is 5-15 degrees, and there are two layers of compact land 10 arranged thereof respectively, and also four of compact land layers can be formed in this embodiment, two compacts 4 are parallelly arranged at the top of the base teeth in the upper compact land along the teeth direction, and three compacts are parallelly arranged at the top of the base teeth in the lower compact land along the teeth direction, and the annular separating grooves 11 are arranged between the compact lands, and the teeth-grooves 12 are made on each of the compact land. 

1. A kind of roller bit with the parallel inlayed compacts, wherein it includes head and cone, the teeth land and the teeth-groove are arranged on the cone, the difference is that there are 2 to 3 compacts having the cylindrical body being arranged on the top of the base teeth along the teeth direction.
 2. The roller bit with the parallel inlayed compacts according to claim 1, wherein the gap between the parallel inlayed compacts may be 2 to 5 mm.
 3. The roller bit with the parallel inlayed compacts according to claim 1 or 2, wherein the crest of the compact is of the wedge shape.
 4. The roller bit with the parallel inlayed compacts according to claim 1 or 2, wherein the base teeth of the compact land (3) can be the shape of straight taper.
 5. The roller bit with the parallel inlayed compacts according to claim 1 or 2, wherein the base teeth of the compact land can be the shape of spiral taper, the spiral angle α is 0 to 15 degrees.
 6. The roller bit with the parallel inlayed compacts according to claim 4, wherein there are 2 to 4 compact lands (3) are arranged on the cone, the annular separating grooves (4) are machined between the compact lands, and the teeth-grooves (6) are made on each of the compact land, from this the base teeth is formed, the base teeth is in the shape of straight taper, the direction of the teeth is the same as the generatrix of the cone body, and also two compacts (2) are parallelly arranged on the top of the base teeth along the direction of the teeth.
 7. The roller bit with the parallel inlayed compacts according to claim 5 wherein there are two compact lands (3) are arranged on the cone, there are two compacts (2) are parallelly arranged at the top of the base teeth in the upper compact lands along teeth direction, and three compacts are parallelly arranged at the top of the base teeth in the lower compact land along the teeth direction, and the annular separating grooves (4) are arranged between the compact lands, and a teeth-grooves (6) are made on each of the compact land.
 8. The roller bit with the parallel inlayed compacts according to claim 1 or 2, wherein the inlayed compacts are made from carbide. 